Need some geometry help

[old man emu]

From Dr Bourke:

It's only a short note on the old page
http://paulbourke.net/geometry/torus/

"Note that with the normal definition of power the above equations are only defined for a single quadrant, namely that where the cosine and sine terms are positive.

When creating the supertorus in practice one has two choices, either replicate the result in the one quadrant to the other three with the correct mirror operations, or define x^n = sign(x) * abs(x)^n."

I guess when I was putting that text together back in 1990 I wasn't paying much attention to those details.

OME